Micro-LED Bonding Structure With Curved ACF Sidewalls for ESD Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The fabrication process of micro-LED displays faces challenges in bonding capabilities and Electrostatic Discharge (ESD) phenomenon, which affect the effective fixation of LEDs and overall display performance.
Innovation Solution
A micro-LED display device is designed with a substrate having a display area and non-display area, featuring light-emitting diodes with contact electrodes and an anisotropic conductive layer with a curved cross-sectional sidewall profile, along with bonding pads and bumps to enhance bonding and reduce ESD by optimizing the angle and size relationships between the substrate, conductive elements, and light-emitting diodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a conventional bonding process is used to fix LEDs on the substrate, then the bonding capability is sufficient for basic assembly, but the bonding strength is insufficient to ensure reliable fixation
Solution Approach 1:
The anisotropic conductive layer is formed with a curved cross-sectional sidewall profile instead of a straight profile. The curvature radius is specifically controlled to be 0.5-2 times the thickness of the anisotropic conductive layer, creating an optimized stress distribution that enhances bonding strength between the substrate and LED while improving fixation reliability
Solution Approach 2:
The invention changes the geometric parameters of the anisotropic conductive layer, specifically the sidewall profile curvature radius and thickness ratio. By optimizing these parameters (curvature radius = 0.5-2 times thickness), the bonding interface achieves improved mechanical interlocking and stress distribution, resolving the contradiction between bonding strength and fixation reliability
2Area of stationary object
If a larger amount of anisotropic conductive material is used to improve bonding coverage, then the bonding area is increased, but the ESD phenomenon is exacerbated
Solution Approach 1:
The curved sidewall profile of the anisotropic conductive layer optimizes the distribution of bonding area while preventing excessive material accumulation. The curvature creates a gradual transition that maintains adequate bonding coverage without forming sharp edges or excessive thickness that would generate ESD, thus resolving the contradiction between bonding area and ESD phenomenon
Solution Approach 2:
The anisotropic conductive layer exhibits different properties in different directions: it provides conductive pathways for electrical connection while the curved profile locally controls material distribution to minimize ESD-prone geometries. This local optimization of material distribution and structure resolves the contradiction between adequate bonding area and reduction of ESD phenomenon
3Ease of manufacture
If the anisotropic conductive layer has a straight cross-sectional sidewall profile, then the manufacturing process is simple, but the bonding capability is insufficient
Solution Approach 1:
The curved sidewall profile is integrated into the existing anisotropic conductive layer formation process through controlled deposition or lamination parameters. While slightly more complex than a straight profile, the curvature is achieved through standard manufacturing adjustments, providing a reasonable balance between manufacturing feasibility and improved bonding capability through optimized stress distribution and mechanical interlocking
Data Source
AI summary
A display device is provided. The display device includes a substrate having a surface including a display area; a plurality of light-emitting diodes disposed on the display area of the substrate, wherein the light-emitting diode includes an electrode; and a plurality of bonding pads disposed on the substrate; a conductive element disposed between one of the plurality of bonding pads and the electrode of the at least one of the plurality of light-emitting diodes; and a first matrix element disposed on the substrate, wherein in a cross-sectional view, the first matrix element is disposed between adjacent two of the plurality of light-emitting diodes, and the electrode has a sidewall profile and at least a part of the sidewall profile of the electrode is in a shape of a curve.